The present invention relates generally to textile tubes or yarn cores, and more particularly relates to a textile tube having at least one start-up recess or groove for capturing textile yarn during a winding operation.
The practice of winding yarn onto tubular carriers during textile production is well known in the art. During high speed production of yarn or thread, the continuously advancing yarn is wound onto consecutive rotating cores or tubes. As a rotating tube encounters a leading strand of the yarn, the tube frictionally engages the yarn to secure an initial wind of the yarn onto the tube and simultaneously break the yarn between the tube and the preceding tube. Therefore, it is important that the tube be able to successfully engage the leading strand of yarn to secure the yarn to the tube and to break the yarn from the preceding tube.
Conventional tubes often employ a xe2x80x9cstart-upxe2x80x9d groove for receiving the leading strand of yarn. The groove is typically xe2x80x9cVxe2x80x9d shaped and formed near one or both ends of the tube by forcing a wedged-shaped tool into the side of the tube. The groove has a xe2x80x9cwidexe2x80x9d section about a portion of the circumference of the tube so that the yarn can locate within the groove, and a xe2x80x9cnarrowxe2x80x9d section for catching and breaking the yarn. Such a groove is disclosed in U.S. Pat. No. 5,328,121, which is assigned to the assignee of the present invention and incorporated herein by reference in its entirety. While the start-up grooves disclosed by the ""121 patent have become an industry standard in the textile winding field, there are still improvements to be made.
It has been discovered that there are occasions where the yarn misses the wide target area of the groove and results in a failed start up, which causes production problems such as downtime and wasted material. There are several reasons why failed start ups occur, among them being (a) variation in yarn tension, (b) improper location of mechanical yarn guides, and (c) variation in groove dimensions. In particular, it has been discovered that the moisture content of the tube can have significant effects on the grooves, as most tubes are formed of paperboard and therefore are somewhat hygroscopic, i.e., capable of gaining and losing moisture. More specifically, a relatively high moisture content of the tube can cause the paperboard to swell, which effectively closes the V-shaped groove and makes successful start ups less likely. Because most textile winding operations are performed in large manufacturing facilities, controlling and maintaining the moisture content and temperature in the surrounding atmosphere is difficult. Thus, there is a need for a tube or core for winding yarn that is less reactive to humidity and other environmental conditions. There is also a need for a yarn tube that allows for easier yarn start-ups.
These and other needs are provided by the textile tube of the present invention, which provides a recessed score around the outer circumference of the body of the tube that provides a significantly wider target for the yarn to engage. As such, successful start-ups are more likely to occur with the tube of the present invention. In addition, the shape of the score of the present invention remains substantially constant regardless of the tube""s moisture content, which thereby overcomes the hygroscopic disadvantages of conventional grooves.
In particular, the textile tube of the present invention is used to support yarn that is wound thereon to form a yarn pack. According to one embodiment of the present invention, the tube comprises a tubular or cylindrical body extending lengthwise between opposed ends thereof and having an outer surface defining an outer diameter of the body. The body defines at least one recessed score at an end thereof that has a flat bottom surface and opposing sidewalls to define a width and depth of the score. The bottom surface extends in a plane that is parallel to the outer surface of the body, and in a preferred embodiment the opposing sidewalls are parallel to one another and perpendicular to the bottom surface of the score. The bottom surface of the recessed score is at least five times the depth and is capable of frictionally engaging or capturing yarn that comes in contact therewith. In one embodiment, the score has a width of between about 0.15-0.20 inches and a depth of 0.01-0.03 inches.
In addition, the bottom surface of the recessed score has an adhesive applied thereto, such as a hot melt adhesive or a double-sided tape. In this regard, the adhesive captures the yarn as the yarn is wound upon the tube. The score is formed such that the adhesive preferably does not extend past the outer surface of the tubular body, which could otherwise cause the tube to stick to an unwanted object that comes in contact therewith.
Advantageously, the recessed score of the present invention substantially retains its shape regardless of the moisture content of the tube. More specifically, the bottom surface and opposing sidewalls form a substantially rectangular cross-section that is more resistant to dimensional changes compared to rounded or V-shaped grooves. And the recessed score of the present invention provides a substantially greater surface area to capture the yarn compared to conventional grooves regardless of the moisture content of the tube.